Travelling wave tube having an elastically mounted helical delay line



Jan. 7, 1964 s ETAL 3,117,250

United States Patent TRAVELLENG WAVE TUBE HAVING AN ELASTICALLY MOUNTED HELICAL DELAY LINE Arthur Kraus and Werner Eichin, Munich, Germany, assignors to Siemens & Halske Aktiengesellschaft Berlin and Munich, a corporation of Germany Filed Sept. 20, 1960, Ser. No. 57,232 Claims priority, application Germany Dec. 9, 1959 Claims. (Cl. 315-35) This invention is concerned with an electron tube, especially a travelling wave tube, having a helical delay line and having means for elastically mounting the helix system of the delay line between two fixedly spaced apart rings extending perpendicular to the longitudinal axis of the tube, thereby overcoming drawbacks resulting from previously known modes of mounting the helix system.

There is a travelling wave tube known having a helix system acting as a delay line for an electromagnetic wave along an electron beam, in which the helix system is fixedly and rigidly secured to two rings which are fixedly spaced apart by means of a vacuumtight envelope. The helix system is accordingly statically disposed in the direction of the tube axis. This static disposition or mounting causes difliculties in the assembly operations and frequently leads to impermissible mechanical stresses incident to the operation of the tube owing to different heat expansion coefficients of the helix system and of the vacuumtight envelope, respectively.

The object of the invention is to avoid the above indicated disadvantages.

This object is in accordance with the invention realized by fastening one end of the helix system in connection with a plane disk which is resiliently journalled in a conical bore of one of the rings by means of a tensioning device engaging the corresponding ring, and by securing the other end of the helix system in connection with a resilient membrane which is cooperatively associated with the other ring.

An advantage of the electron tube according to the invention resides in the fact that stresses, caused by heat expansion in the longitudinal direction of the tube, are equalized due to the elastic fastening or mounting of the helix system between the two rings which delimit the space of reciprocal action between the electron beam and the electromagnetic wave. The helix system is moreover centered in the tube by the plane disk disposed in the conical bore of one of the rings. The assembly of the helix system is rendered very simple since it can be tensioned by the tenisoning device after being put in place in the tube.

It is of particular advantage in a structure according to the invention, to fasten the end of the helix system facing the cathode, by means of the resilient membrane, such fastening of the corresponding end of the helix system permitting tensioning thereof by the tensioning device at the collector end.

A further advantageous feature of the electron tube according to the invention resides in fastening each end of the helix to an antenna tube which is fixedly connected with the plane disk and with the membrane, respectively. The antenna tubes with which the helix is electrically conductively connected, are respectively connected with the membrane cooperating with one of the rings and with the plane disk cooperatively associated with the other ring, so as to permit connection, to the respective rings, of the wave guide input and wave guide output for the electromagnetic Wave.

An electron tube of the type of a travelling wave tube is in most cases widened at the end thereof at which is positioned the radiation generating system. The vacuum- 3,117,250 Patented Jan. 7, 1964 tight transistion from the widened part of the vacuum vessel which contains the radiation generating system, to the relatively narrow part thereof, is effected by means of a metal ring forming a shoulder. in accordance with the invention, it is of advantage to fasten the membrane at a ring which is centered in this shoulder ring.

The invention and the various objects and features thereof shall now be explained with reference to the accompany'ing drawing showing in simplified and in part schematic manner, an embodiment thereof.

The envelope 1 embraces in vacuumtight manner the space of reciprocal action between the electron beam and the electromagnetic wave propagated upon the helix 2, such space being in the longitudinal direction delimited with regard to the beam producing system, comprising the cathode 3, by the shoulder ring 4 and with regard to the collector 5, by the intermediate ring 6. The shoulder ring 4 forms the connecting part between the wall 7 of the widened portion of the vacuum vessel and the beam generating system, and the envelope 1 defining the space of reciprocal action. The wall 7 and the envelope 1 are as a rule made of glass or ceramic material. The collector 5 is electrically insulated from the intermediate ring 6 by a glass or ceramic member 8 which is fused to the intermediate ring 6.

The opposite ends of the helix 2 are respectively connected with tubular antenna members 9* and 10. The tubular antenna member 9 is at the cathode side fastened to the membrane 11 which is in turn carried by the mem brane ring 12, the latter being disposed in a bore in the shoulder ring 4 so that the helix is centered with respect to the axis of the tube. At the collector end of the electron tube, the antenna tubing 10 is connected with a plane disk 13 made of elastic material. This plane disk is provided with an extension having a thread on the side facing away from the antenna tubing 10, such threaded extension projecting through a bore with conical flank. A nut 14 disposed at the collector side is threaded upon the threaded extension, such nut operating on the intermediate ring in such a manner that the disk '13 is elastically positioned between the conical flanks of the bore in the intermediate ring 6.

The parts serving for the fastening or mounting of the helix system, that is, the antenna tubings 9 and 10, the membrane ring 12, the membrane 11, the plane disk 13 and the nut 14, and also the shoulder ring 4 and the intermediate ring 6, are appropriately made of electrically conductive material, so as to permit connection of the coupling wave guide 15 and the decoupling wave guide 1-6, respectively, directly to the rings which delimit the space of reciprocal action.

The invention is not inherently limited to the illustrated example, but can be advantageously employed in all applicable situations in which a helical delay line is to be disposed between two mutually fixedly spaced rings.

Changes and modifications may be made within the scope and spirit of the appended claims which define what is believed to be new and desired to have protected by Letters Patent.

We claim:

1. An electron tube of the travelling wave type, comprising a helical delay line including a helix system disposed between two rigidly spaced part rings which extend respectively perpendicularly to the longitudinal axis of the tube, one of said rings having a conical bore formed therein, a plane disk, a tensioning device cooperatively associated with said one ring for resiliently journalling said disk in said conical bore, means for fastening one end of said helix system in connection with said disk, a membrane cooperatively associated with the other ring, and means for fastening the other end of said helix system in connection with said membrane.

2. An electron tube according to claim 1, wherein the end of said helix system fastened to said membrane faces in the direction of the cathode of said tube.

3. An electron tube according to claim 2, comprising an antenna tubing connected with each end of the helix of said delay line, said tubings being respectively fastened to said disk and said membrane.

4. An electron tube according to claim 3, wherein the respective antenna tubings are respectively over said disk and said membrane electrically conductively connected with the respective rings.

5. An electron tube according to claim 4, having a vacuum vessel comprising a relatively narrow portion 4 containing said helix system and a relatively wide portion containing the radiation generating system, a shoulder ring extending between and interconnecting such portions, said membrane-carrying ring being centered in said shoulder ring.

References Cited in the tile of this patent UNITED STATES PATENTS 2,682,623 Woodyard et a1. June 29, 1954 2,716,202 Little Aug. 23, 1955 2,888,600 Rich May 26, 1959 2,934,671 Rich Apr. 26, 1960 

1. AN ELECTRON TUBE OF THE TRAVELLING WAVE TYPE, COMPRISING A HELICAL DELAY LINE INCLUDING A HELIX SYSTEM DISPOSED BETWEEN TWO RIGIDLY SPACED PART RINGS WHICH EXTEND RESPECTIVELY PERPENDICULARLY TO THE LONGITUDINAL AXIS OF THE TUBE, ONE OF SAID RINGS HAVING A CONICAL BORE FORMED THEREIN, A PLANE DISK, A TENSIONING DEVICE COOPERATIVELY ASSOCIATED WITH SAID ONE RING FOR RESILIENTLY JOURNALLING SAID DISK IN SAID CONICAL BORE, MEANS FOR FASTENING ONE END OF SAID HELIX SYSTEM IN CONNECTION WITH SAID DISK, A MEMBRANE COOPERATIVELY ASSOCIATED WITH THE OTHER RING, AND MEANS FOR FASTENING THE OTHER END OF SAID HELIX SYSTEM IN CONNECTION WITH SAID MEMBRANE. 